What type of gas do you run?

[Fredensborg]

I got some great...but spendy...news from my mechanic!! After rebuilding my carb, putting in new spark plugs and supplying it with fresh gas from a bottle my Mustang is running great!! I even got to stop by and listen to her growl One of my mufflers was also split down the seam and the gas tank has a bunch of nasty rusty sludge in it from sitting. We have a new gas tank and muffler on the way, so in a few days and about 1300 dollars later I should have my car back and patrolling the streets of central Minnesota!! My question is this..What gas should I run in it? In the past I have just put in 91 octane, but the gas around here has that 10-15% corn piss in it that I have heard is horrible for old engines and I really don't want to deal with these issues again. There are some gas stations around that have "non-oxy premium" will that do the trick? Or is there some additive I should use? After basically replacing the entire fuel system, I want to keep it in as good of shape as I can for as long as I can.

 

[Don C]

https://www.pure-gas.org/

 

[73pony]

91 or higher octane with no ethanol. Not the easiest to find but it is out there.

 

[Fredensborg]

https://www.pure-gas.org/

Sweet! Looks like there are several in my area, thanks Don.

 

[Ed Raver]

I run 91 octane without ethanol in all my cars. I have had no issues at all. Even my chain saws get the good stuff. Ed

 

[Carolina_Mountain_Mustangs]

Gosh my computer went crazy took a day to get going again.

Like said no Ethanol if possible. Make sure your mechanic changes all the rubber hoses from the gas tank to the carburator to ethanol resistant material. Lots of carburetor kits are the old rubber and the ethanol turns the rubber parts to gummy pieces.

I am able to get ethanol free a mile from home at a Citgo here. I think $3.25 a gallon and 92 or 93 octane. In my area Sunoco also keeps good fuel for the racers in the area going to I think 110 octane. Now if you are like a friend that has around 15 to 1 compression he pays about $21.00 a gallon for his fuel.

I do put Stabile in my fuel and you should always keep the tank all the way full or all the way empty. If your fuel pump is older the ethanol will degrade the rubber diaphragm and your oil level will rise in the pan. That is because the gas is going into the oil pan. All the rubber parts in the carb. fail due to the ethanol also.

It is a huge issue not just with our older cars. Some Chryslers have huge fuel pump issues in the gas tank.

My car sat for 26 years so the gas tank was spotless when I removed. The ethanol causes rust and all the corrosion we see very quick.

David

 

[delawarebill]

we have E10 everywhere here and i need to travel about 40+ miles to get the good stuff.. Sooo i add lead additive to fuel now and then. my motor does not like reg and it pings so high test is my only option... driving around 1000/yr so not big deal.

 

[Stanglover]

https://www.pure-gas.org/

Nice find Don, As I'm in Ontario Canada, it's nice to know I can get my gas at Canadian Tire far cheaper than Shell. Apparently Can Tire buy from Shell anyway, but not sure if it has the same additives. 91 octane is currently around 5.75 Can. per US gallon here or 1.52/liter, so that's about 4 bucks US a gallon.

Geoff.

 

[donkost]

The transport company owner that delivered my last car saw my '71 Mach 1 429 CJ-R and said I should be running this:

https://vpracingfuels.com/product/vp-110/

Lol. Anyone else notice that the ethanol-blended gas stinks like $hit? When I was a kid I used to enjoy the smell of real gas when I went along on a fill-up with my dad. On modern closed system fuel injected vehicles you really don't smell the fuel. But on a old-school carbureted vehicle, when you park in the garage after a good run and close the garage door, that corn juice / gas smell will permeate the area. I guess we're pretty much stuck with that fuel for life. More and more people are getting on board with what a boondoggle it is for the various parties involved.

 

[Stanglover]

Recently, I posted about my first (and likely only) trip to the drag strip in 'Mustang Talk'

Before I went and as I needed fuel anyway, I put in about 8 gallons of Petro-Canada (formerly Sunoco) 94. Since being taken over, the good stuff is now *******ized with 10% Ethanol. To sweeten it up, I added a bottle of Lucas Racing Octane Boost. I absolutely noticed the difference. The car pulled like a train. I've been working for some time on timing as most will know and was able to rev to 5K without any rattle. Now, when I got home and it cooled down, I wanted to check my plugs for color. They were nice and clean all around meaning a nice clean burn, but they were RED colored!! I guess from the Lucas. A bit hard to get a true read of fuel/air mixture, but it can't be too far off.

Will I run 94 again, not too likely. I find the 91 Shell or equivalent, runs fine ordinarily in my 10:1 engine. Compression, cam, timing, carb size, jetting all play a big part in determining the fuel you'll need and I'm pretty sure the likes of Don C will agree.

Geoff.

 

[Stanglover]

The transport company owner that delivered my last car saw my '71 Mach 1 429 CJ-R and said I should be running this:

https://vpracingfuels.com/product/vp-110/

Lol.  Anyone else notice that the ethanol-blended gas stinks like $hit?  When I was a kid I used to enjoy the smell of real gas when I went along on a fill-up with my dad.  On modern closed system fuel injected vehicles you really don't smell the fuel.  But on a old-school carbureted vehicle, when you park in the garage after a good run and close the garage door, that corn juice / gas smell will permeate the area.  I guess we're pretty much stuck with that fuel for life.  More and more people are getting on board with what a boondoggle it is for the various parties involved.

 YES!!!

 

[Mach_One]

Finding non-ethanol gas around here (Nebraska) is not hard.  Most places have 87 octane E-10, 89 octane (no ethanol) and 91 octane premium.  I can't find 93 octane anywhere around here.  My engine pings like popcorn on the 91 premium, and those miracle-in-a-bottle octane boosters don't work.  I resorted to mixing my gas 50/50 premium gas and LL100 octane avgas.  No ping, the 429CJ-R runs strong.  Buying, hauling and mixing gas is a hassle, but you sacrifice for the ones you love!

 

[Stanglover]

Finding non-ethanol gas around here (Nebraska) is not hard.  Most places have 87 octane E-10, 89 octane (no ethanol) and 91 octane premium.  I can't find 93 octane anywhere around here.  My engine pings like popcorn on the 91 premium, and those miracle-in-a-bottle octane boosters don't work.  I resorted to mixing my gas 50/50 premium gas and LL100 octane avgas.  No ping, the 429CJ-R runs strong.  Buying, hauling and mixing gas is a hassle, but you sacrifice for the ones you love!

 I'm not familiar with 429's at all, but if they behave anything like a 71 351C 4V M code, you might want to look at your distributor for degrees and curve. Mine pinged like popcorn too until I finally figured out HOW  to build a distributor. I've posted on this many times if you care to search just to give you an idea. I can now run on 91 non-ethanol without any pinging. My settings are; 10L slot width (.410") or 20degrees on the crank, 1 factory heavy spring set to just loose on the pegs and 1 Mr.Gasket 925D set with mild tension. The initial is currently at 16 degrees for a total of 36* total mechanical plus about 6 deg. of vacuum advance. This is on a Motorcraft factory dist. Non of that HEI sh*t for me. Many of the reman distributors I found are built with a 15L slot or 30 deg. crank, which only allows about 4-6 deg. of initial before you run into too much advance, hence pinging with any more. I also run a Pertronix Ignitor II and coil.

EDIT: I did not mention my engine is a modest 10:1 with a mild cam just slightly above stock. 64 cc CC heads, stock intake and exhaust manifolds.

My fuel system is now also upgraded to tolerate ethanol IF I have too. Our Sunoco 94, owned by Petro-Canada, is now 10% corn crap.

Of course if you motor is built up super high, no amount of timing mods will fix it as far as I know...……… which isn't much!!

Geoff.

 

[c9zx]

The Torco and VP octane boosters do work as advertised. I've run Torco in cars with O2 sensors and VP in the older cars. As has been previously stated, too much timing, too tame of a cam, too much compression, and low octane fuel all contribute to "pinging", detonation/pre-ignition. Chuck

 

[Jeff73Mach1]

Based upon my personal tail pipe emissions it appears I run on Methane :atomic:

 

[Mach_One]

Finding non-ethanol gas around here (Nebraska) is not hard.  Most places have 87 octane E-10, 89 octane (no ethanol) and 91 octane premium.  I can't find 93 octane anywhere around here.  My engine pings like popcorn on the 91 premium, and those miracle-in-a-bottle octane boosters don't work.  I resorted to mixing my gas 50/50 premium gas and LL100 octane avgas.  No ping, the 429CJ-R runs strong.  Buying, hauling and mixing gas is a hassle, but you sacrifice for the ones you love!

 I'm not familiar with 429's at all, but if they behave anything like a 71 351C 4V M code, you might want to look at your distributor for degrees and curve. Mine pinged like popcorn too until I finally figured out HOW  to build a distributor. I've posted on this many times if you care to search just to give you an idea. I can now run on 91 non-ethanol without any pinging. My settings are; 10L slot width (.410") or 20degrees on the crank, 1 factory heavy spring set to just loose on the pegs and 1 Mr.Gasket 925D set with mild tension. The initial is currently at 16 degrees for a total of 36* total mechanical plus about 6 deg. of vacuum advance. This is on a Motorcraft factory dist. Non of that HEI sh*t for me. Many of the reman distributors I found are built with a 15L slot or 30 deg. crank, which only allows about 4-6 deg. of initial before you run into too much advance, hence pinging with any more. I also run a Pertronix Ignitor II and coil.

EDIT: I did not mention my engine is a modest 10:1 with a mild cam just slightly above stock. 64 cc CC heads, stock intake and exhaust manifolds.

My fuel system is now also upgraded to tolerate ethanol IF I have too. Our Sunoco 94, owned by Petro-Canada, is now 10% corn crap.

Of course if you motor is built up super high, no amount of timing mods will fix it as far as I know...……… which isn't much!!

Geoff.

You are right, I should have a look at the distributor.  My 429CJ is completely stock with points in the distributor and 11:3:1 compression.  She'd ping like crazy anytime I dropped the hammer.  Avgas makes her happy.  Thanks for the info!

 

[Mikes73]

Excellent post and great advice. A self tuned distributor is the way to go. Duraspark distributors work great, I use them on all of my Ford builds with great results.

 

[Stanglover]

Removed old posts to save space!

You are right, I should have a look at the distributor.  My 429CJ is completely stock with points in the distributor and 11:3:1 compression.  She'd ping like crazy anytime I dropped the hammer.  Avgas makes her happy.  Thanks for the info!

 But Avgas gets VERY expensive!! Premium is bad enough!

 As mentioned, a Dura Spark is a good distributor by all accounts and you can buy them built and tuned for YOUR engine. I think the company is Performance Distributors, not sure without double checking.

Again I make no claim to be an expert, but to me it seems like as you are running points in an old dizzy, I'd be looking a getting a rebuilt Motorcraft or Dura Spark and if necessary re-slotting the smallest slot as required for the 429's best max initial advance. Like I also said, I'm not familiar with the big engines, so do your research. 351's like 14 to 16 degrees of initial, but only tolerate 34 -36 max mechanical, therefore only 20 deg. on the crank (10L slot) and this also may be dependent on the build of a particular engine. This is what I have come to learn over the last 10 years, largely from my own experimentation.

Good luck with it,

Geoff.

 

[Mach_One]

Removed old posts to save space!

You are right, I should have a look at the distributor.  My 429CJ is completely stock with points in the distributor and 11:3:1 compression.  She'd ping like crazy anytime I dropped the hammer.  Avgas makes her happy.  Thanks for the info!

 But Avgas gets VERY expensive!! Premium is bad enough!

 As mentioned, a Dura Spark is a good distributor by all accounts and you can buy them built and tuned for YOUR engine. I think the company is Performance Distributors, not sure without double checking.

Again I make no claim to be an expert, but to me it seems like as you are running points in an old dizzy, I'd be looking a getting a rebuilt Motorcraft or Dura Spark and if necessary re-slotting the smallest slot as required for the 429's best max initial advance. Like I also said, I'm not familiar with the big engines, so do your research. 351's like 14 to 16 degrees of initial, but only tolerate 34 -36 max mechanical, therefore only 20 deg. on the crank (10L slot) and this also may be dependent on the build of a particular engine. This is what I have come to learn over the last 10 years, largely from my own experimentation.

Good luck with it,

Geoff.

Yeah, spendy!  Good thing it's not a daily driver!  Last time I bought avgas, it was $4.00/gal.  Since there's no road tax, they won't put it in your car.  They'll sell it, just not put it in!  I can haul about 22 gallons of avgas in 3 gas cans that I have.  It's enough for a few tanks of mix gas.  The old boy at the airport looks at me and grins and says: "What do you got that you need avgas for?" "429 Cobra Jet" I reply.  He grins even bigger after hearing that and proceeds to tell me how the drag racers come over with their 55-gallon drums to get them filled, LOL!

My car is restored and the engine is completely stock/original with correct dizzy and points in it.  I don't want to change rather keep it original.  Timing and advance curve are still worth looking at though.  Thanks!